Today at Culture Club  we discussed a recent paper by Eerkens & Lipo [link], where they present a null model of copying errors in cultural transmission. One of the notions they discuss is something I learnt a million years ago in Stage 1 Experimental Psychology: Weber's Fraction, or the Just Noticeable Difference. Interestingly, they reference the exact textbook from which I learnt psychophysics (wow, textbooks are expensive, I had forgotten!).
This made me think about what sort of "perceptual limits" there might be for complex social phenomena like kinship organisation, and where the JND might lie in scales of difference in (for example) inheritance. What would be the so-called "tipping point" for a formerly matrilineal system to start adopting as a norm a system of bilateral inheritance? What might the units to examine be? It struck me that this is possibly a way to get at some thorny "units of culture" questions, although it is beyond the scope of what I'm doing at present. But it would be so very nice to have some sort of null model that might group perceptually-bounded culture concepts together.
 Our weekly journal club/discussion meeting for the Centre for the Evolution of Cultural Diversity.